Basically you need to get some fine grit sand paper at pep boys, 600 to a 1000 grit. It involves taping the sandpaper to your desk, starting out at a low fine grit and working your way up a higher grit. You'd rotate the processor after each set. I think I went up to 800 grit before.

Youtube has videos of this.

Oh and doing this is a complete waste of time IMO. Better off buying a corsair h50/h70 or antec kuhler 620/920 then wasting time doing this junk.

i havent lapped my cpu as it is still under warranty but i lapped my corsair h50 with 400/600/1500 sandpaper to a mirror finish (dont ask me why i used 1500 they didnt have anything between 600-1500 *napa auto parts*) but anyways, i got ~ a 5c max load drop in temps. hottest core before was 84-85c max and now its 79-80c max so lapping DOES help. I dont have any experience on the cpu tho so try it out and see! u have nothing to lose!

You want to make sure your surface is flat, i used a mirror and taped the sandpaper to it using painters tape. You also don't want to push down on the CPU this will cause the surface to be lop sided. let the wait of the CPU do the job.

TJ Harlow did a video a few years ago on how to do lapping the proper way. Ill link it below.